1. Field of the Invention
The present invention relates to a recoil starter, wherein a recoil rope wound around a reel is pulled so as to rotate the reel, and thus transmit rotation of the reel to a rotating member connected to an engine through a centrifugal ratchet, to thereby start the engine by means of rotation of the rotating member.
2. Description of the Related Art
A conventionally known recoil starter is constituted, as shown in FIG. 6, so that a reel 21, which is rotatably supported in a casing 20 and which has a rope 22 wound therearound and a cam 23 formed thereon, and a centrifugal ratchet 24 provided on a pulley 25 connected with a crank shaft of an engine are arranged in association with each other so as to permit the cam 23 to be engaged with the centrifugal ratchet 24. When the rope 22 wound around the reel 21 is pulled to rotate the reel 21, the pulley 25 is driven to be rotated via the cam 23 on the real 21 and the centrifugal ratchet 24 on the pulley 25, whereby the engine is started. Another conventional recoil starter includes, as shown in FIG. 7, a centrifugal ratchet 24 which is provided on a flywheel magnet 26 coupled with a crank shaft of an engine so as to be engageable with a cam 23 formed on a reel 21. However, in the conventional recoil starters having the above structure where the cam 23 and the reel 21 are integrally formed, a shock caused at a compression stroke of the engine during a starting operation is transmitted directly to a hand of an operator which pulls the rope 22 via a rotating member coupled with the crank shaft, such as the pulley 25 or the flywheel magnet 26. For this reason, the starting is troublesome. In addition, when the engine is stopped, a shock of engagement between the ratchet and the cam due to reverse rotation of the engine is transmitted to the entire recoil starter, thereby causing damage to the recoil starter.
In order to solve the above problem, a recoil starter provided with a damper spring which is disposed between a reel and a cam so that the reel and the cam are connected with each other therethrough was proposed and is disclosed in Japanese Utility Model Publication No. 6-16964. In this technique, the cam which is rotatable in relation to the reel is provided, and the cam and the reel are connected by the damper spring, so that an abrupt load at the time of starting the engine is absorbed by deformation of the damper spring, whereby an impulsive load is attenuated and simultaneously a rotating force is stored. When the load becomes small after the compression stroke, the rotating force which has been stored in the damper spring is discharged so as to acceleratingly rotate the pulley and facilitate the starting of the engine. Moreover, when the engine is stopped, a shock of the engagement due to the reverse rotation of the engine is absorbed by the damper spring, leading to an advantage that the starter is not overstrained.
However, in the technique described above, it is required that the cam which is engageable with the centrifugal ratchet disposed on the pulley be arranged so as to be rotatable in relation to the reel and that a member for rotatably supporting the cam be provided. Further, a large space is necessary to receive the cam and the damper spring connected to the cam. Therefore, this technique has problems in that the structure of the starter becomes complicated and thus miniaturization of the starter becomes difficult.
The present invention has been made in view of the foregoing disadvantages of the prior art.
Therefore, it is an object of the present invention to provide a recoil starter which has a reduced number of components and a simple structure, and which enables miniaturization and a cost reduction.
In accordance with the present invention, a recoil starter for an engine is provided. The recoil starter comprises: a rotatable reel; a recoil rope wound around the reel and arranged so as to drive the reel to rotate it; a recoil spring for urging the reel in a rope rewinding direction; a centrifugal ratchet provided on a rotating member of the engine; and a damper spring disposed between the reel and the centrifugal ratchet; wherein the damper spring has one end fixed to the reel and is provided at the other end thereof with an operation section; and the operation section of the damper spring is arranged to disengageably engage with the centrifugal ratchet so as to transmit rotation of the reel rotated by the recoil rope to the rotating member of the engine through the ratchet, so that a shock caused by the engine is absorbed by the damper spring and a rotating force on the reel is stored by the damper spring.
In a preferred embodiment of the present invention, the reel is formed therein with an annular recess facing the rotating member of the engine, in which recess the damper spring is received.
In a preferred embodiment of the present invention, the recoil starter further comprises a casing for receiving therein the reel, wherein the casing is provided on an inner surface thereof with a shaft for rotatably supporting the reel, which shaft is protruded from the inner surface and formed concentrically with the annular recess of the reel.
In a preferred embodiment of the present invention, the annular recess of the reel is provided on a bottom thereof with a holding protrusion; and the damper spring comprises a torsion coil spring which is provided at the one end thereof with an engaging portion engaged with the holding protrusion and provided at the other end thereof with the operation section formed by a portion protruding from an outer periphery of the torsion spring and being bent into an axial direction.
In a preferred embodiment of the present invention, the rotating member of the engine comprises a pulley connected to a crank shaft of the engine. Alternatively, the rotating member of the engine may comprise a flywheel magnet operatively connected to a crank shaft of the engine.